Serotonin syndrome is a rare but potentially life-threatening condition when there's too much serotonin in the brain. The dextromethorphan in Coricidin Hbp Cough And Cold (Chlorpheniramine / Dextromethorphan), when used with other medicines that affect serotonin (antidepressants, lithium, triptans, St. John's wort), increases your risk for serotonin syndrome. Symptoms include fast heart rate, sweating, muscle stiffness or spasms, fever, and confusion. Get medical attention right away if you have these symptoms.

Common concerns from people taking Coricidin Hbp Cough And Cold (Chlorpheniramine / Dextromethorphan)